The objective of this protocol is to test a hydrogel implant releasing the LHRH agonist [(ImBzl)-D-His6, Pro9-Net]-LHRH (LHRH-13) in men. When this potent agonist is released from such implants it is expected to suppress LH, FSH and testosterone for up to one year. This treatment can be used as a component of a male contraceptive as well as for treatment of prostate cancer and benign prostatic hyperplasia (BPH).